"I don't know if we want to play spoiler, but we want to give these guys some experience and a feel for what's it like to compete against top-notch teams," said interim manager Tony DeFrancesco.

Even if they're doing it with a patchwork roster that now includes Gonzalez, a 29-year-old journeyman who was pitching in the Mexican League earlier this summer before signing a minor league deal with Houston on Aug. 23.

Less than two weeks later the right-hander made his first major league start since 2009 and ended up with his first win as a starter since April, 24, 2008 when he was pitching in Arizona.

"It's been a while," Gonzalez said. "The last start was in '09. I felt great, I was just so focused and threw the ball down and thank God that things worked good for us."

Gonzalez gave up a run on five hits in 5 1/3 innings, walking one and striking out five as the Astros won for just the third time since DeFrancesco took over two weeks ago.

"Since I've been here, the fight's been there every game," DeFrancesco said. "I have no problem with the way guys are competing. ... They're starting to have fun, getting on each other and in the dugout. There's a lot of life."

Something the reeling Pirates could use. In the midst of a playoff race for the first time in 20 years, Pittsburgh has dropped four straight and 10 of its last 13 and trails St. Louis by 2½ games for the NL's second wild card spot.

"We've got to keep going," said Pirates right fielder Garrett Jones, who had three of Pittsburgh's five hits. "We've got to keep our heads high, keep our confidence high and get 'em tomorrow."

The release of veteran left-hander Erik Bedard and an injury to Jeff Karstens has forced the Pirates to juggle their starting rotation. They turned to Jeff Locke, hoping the 24-year-old lefthander could give the staff a boost.

It didn't quite happen. Locke (0-1) surrendered five runs in five innings to remain winless in five big league starts. Though he pitched efficiently -- striking out six and walking just one -- the Astros took advantage of his mistakes.

None of them bigger than a hanging breaking ball to Wallace with two on in the sixth.

Jose Altuve singled with one out and Tyler Greene followed with a chopper to Pittsburgh shortstop Clint Barmes, who double-clutched on his throw to first to give Greene just enough time to beat it out for a hit. Wallace sent Locke's next offering into the first row of seats in right-center for his seventh homer of the season.

"I think the biggest thing is we're playing with energy," Wallace said. "You see the whole team come together. We're trying to turn this thing around, like Tony said. We're going to play with energy and work hard and see what we can do. It's fun to play in that atmosphere, and I think the guys are really buying in."

The homer gave Gonzalez all the breathing room he would need.

The 29-year-old has bounced between four organizations since making his debut with Arizona in 2003. It's been a long journey over the last three years as he's tried to salvage his career.

Gonzalez hardly looked nervous, however, with the ball in his hand. He threw first seven pitches for strikes and was met with little resistance by the Pirates.

"I throw different," Gonzalez said. "In `09, I just threw a lot of fastballs and a slider. Right now I throw changeups, curveballs, (cutters) in every count, so I feel much better."

Game notes

Pittsburgh 2B Neil Walker (back) began baseball activities and could return to the team by Friday. Walker hasn't played since Aug. 26 ... Karstens has been cleared to do "flat ground" work but there remains no timetable for his return. Karstens left Friday's loss in Milwaukee in the first inning with what's been diagnosed as a hip flexor strain ... The series continues on Tuesday when Pittsburgh's Wandy Rodriguez (9-13, 3.86 ERA) faces Houston's Jordan Lyles (3-10, 5.46) ... The Astros are 3-10 under DeFrancesco ... Houston recalled C Carlos Corporan, RHP Chuckie Fick, LHP Dallas Keuchel and OF J.D. Martinez after the game.